4.1.46-rt52-rc1 stable review patch. If you have any objection to the inclusion of this patch, let me know. --- 8< --- 8< --- 8< --- Upstream commit 5b95e1af8d17d ("workqueue: wq_pool_mutex protects the attrs-installation") introduced an additional assertion (assert_rcu_or_wq_mutex_or_pool_mutex) which contains a check ensuring that the caller is in a RCU-sched read-side critical section. However, on RT, the locking rules are lessened to only require require _normal_ RCU. Fix up this check. The upstream commit was cherry-picked back into stable v4.1.19 as d3c4dd8843be. This fixes up the bogus splat triggered on boot: =============================== [ INFO: suspicious RCU usage. ] 4.1.42-rt50 ------------------------------- kernel/workqueue.c:609 sched RCU, wq->mutex or wq_pool_mutex should be held! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 0 2 locks held by swapper/0/1: #0: ((pendingb_lock).lock){+.+...}, at: queue_work_on+0x64/0x1c0 #1: (rcu_read_lock){......}, at: __queue_work+0x2a/0x880 stack backtrace: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.1.42-rt50 #4 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-20170228_101828-anatol 04/01/2014 Call Trace: dump_stack+0x70/0x9a lockdep_rcu_suspicious+0xe7/0x120 unbound_pwq_by_node+0x92/0x100 __queue_work+0x28c/0x880 ? __queue_work+0x2a/0x880 queue_work_on+0xc9/0x1c0 call_usermodehelper_exec+0x1a7/0x200 kobject_uevent_env+0x4be/0x520 ? initcall_blacklist+0xa2/0xa2 kobject_uevent+0xb/0x10 kset_register+0x34/0x50 bus_register+0x100/0x2d0 ? ftrace_define_fields_workqueue_work+0x29/0x29 subsys_virtual_register+0x26/0x50 wq_sysfs_init+0x12/0x14 do_one_initcall+0x88/0x1b0 ? parse_args+0x190/0x410 kernel_init_freeable+0x204/0x299 ? rest_init+0x140/0x140 kernel_init+0x9/0xf0 ret_from_fork+0x42/0x70 ? rest_init+0x140/0x140 Reported-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> Signed-off-by: Julia Cartwright <julia@xxxxxx> --- kernel/workqueue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 6bdcab98501c..90e261c8811e 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -363,7 +363,7 @@ static void workqueue_sysfs_unregister(struct workqueue_struct *wq); "RCU or wq->mutex should be held") #define assert_rcu_or_wq_mutex_or_pool_mutex(wq) \ - rcu_lockdep_assert(rcu_read_lock_sched_held() || \ + rcu_lockdep_assert(rcu_read_lock_held() || \ lockdep_is_held(&wq->mutex) || \ lockdep_is_held(&wq_pool_mutex), \ "sched RCU, wq->mutex or wq_pool_mutex should be held") -- 2.14.2 -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html